ObjectiveTo systematically review the efficacy of vitamin D supplementation on patients with polycystic ovary syndrome (PCOS).MethodsPubMed, EMbase, The Cochrane Library, Web of Science, EBSCO, CBM, WanFang Data, CNKI and VIP databases were electronically searched to collect randomized controlled trials (RCTs) on the efficacy of vitamin D supplementation for PCOS from inception to July 2019. Two reviewers independently screened literature, extracted data and assessed risk of bias of included studies, then, meta-analysis was performed by using RevMan 5.3 software.ResultsA total of 11 RCTs involving 692 patients were included. The results of meta-analysis showed that compared with placebo, vitamin D could reduce the level of hypersensitive C-reactive protein (hs-CRP) (MD=−0.54, 95%CI −1.00 to −0.08, P=0.02) and total testosterone (MD=−0.17, 95%CI −0.29 to −0.05, P=0.004), and increase endometrial thickness (MD=1.78, 95%CI 0.49 to 3.06, P=0.007). However, there were no significant differences between two groups in the incidence of sex hormone binding globulin (SHBG) level and hypertrichosis’s score (mF-G) (P>0.05).ConclusionsCurrent evidence indicates that vitamin D supplementation can significantly reduce the level of total testosterone and hs-CRP, and increase endometrial thickness of PCOS. Due to the limited quality and quantity of the included studies, more high quality studies are required to verify the above conclusions.
ObjectiveTo systematically review the effects of assisted reproductive technology in single pregnancy on the incidence of gestational diabetes.MethodsPubMed, EMbase, The Cochrane Library, Web of Science, CNKI, WanFang Data, VIP and CBM databases were electronically searched to collect cohort studies on the correlation between assisted reproductive technology (ART) and gestational diabetes mellitus (GDM) incidence in single pregnancy from inception to June 2019. Two reviewers independently screened literature, extracted data and assessed risk of bias of included studies. Meta-analysis was then performed by using RevMan 5.3 software.ResultsA total of 16 cohort studies involving 2 017 573 cases of single pregnancy were included. The results of meta-analysis showed that compared with the natural pregnancy group, the incidence of GDM was higher in the ART group (RR=1.54, 95%CI 1.30 to 1.83, P<0.000 01). In East Asia and Non-East Asia, the incidence of GDM in the ART group was higher than that in the natural pregnancy group (East Asia: RR=1.55, 95%CI 1.26 to 1.92, P<0.000 01; Non-East Asia: RR=1.49, 95%CI 1.18 to 1.89. P<0.000 1).ConclusionsCurrent evidence shows that the incidence of GDM may increase in single pregnancy with ART compared with natural pregnancy. Due to limited quantity and quality of the included studies, more high quality studies are required to verify above conclusions.
ObjectivesTo systematically review the correlation between maternal serum selenium levels during pregnancy and premature birth.MethodsDatabases including PubMed, The Cochrane Library, EMbase, Web of Science, CNKI and CBM were searched to collect studies on correlation between maternal serum selenium levels during pregnancy with preterm birth in the offspring from inception to January, 2020. Two reviewers independently screened literature, extracted data and evaluated risk of bias of the included literature. Then, meta-analysis was conducted by using RevMan 5.3 software.ResultsA total of 12 studies involving 2 484 patients were included. The results of meta-analysis showed that compared with control group, the preterm group had lower serum selenium levels in pregnant females (SMD=−0.89, 95%CI −1.56 to −0.22, P=0.01). The results of the subgroup analysis showed that heterogeneity among subjects was still large when grouped accorcding to the continent to which a country belongs, the time of blood sample collection and test method in pregnant females.ConclusionsLow maternal serum selenium levels during pregnancy may increase the risk of preterm birth. Due to the limitation of the quantity and quality of the included studies, the above conclusions are required to be verified by more high quality studies.
ObjectiveTo systematically review the relationship between cadmium (Cd) and childhood autism.MethodsPubMed, EMbase, Web of Science, The Cochrane Library, CNKI, VIP, WanFang Data and CBM were electronically searched to collect case-control studies on the relationship between Cd and childhood autism from inception to July 2019. Two reviewers independently screened literature, extracted data and assessed the risk of bias of included studies. Then, meta-analysis was performed by using RevMan 5.3 software.ResultsA total of 8 case-control studies were included. The results of meta-analysis showed that whether the specimen was from whole blood, urine or hair, there were no correlations between Cd and childhood autism (MDblood=0.17, 95% CI −0.06 to 0.39, P=0.15; MDurine=−0.43, 95%CI −1.44 to 0.58, P=0.4; MDhair=−0.08, 95%CI −0.52 to 0.36, P=0.72).ConclusionsCurrent evidence shows that Cd concentration is not correlated with autism in children. Due to limited quality and quantity of the included studies, more high quality studies are required to verify above conclusions.